Today's engine systems often utilize exhaust gas recirculation (EGR) to return a portion of exhaust gas to an intake manifold to reduce pumping work and/or help with combustion including combusting any unburned fuel or byproducts present in the recirculated exhaust gas. In this manner, EGR is a known method for pumping work reduction, knock control and CO2 emissions reduction as well as reduction of Nitrogen Oxide (NOx) emissions of internal combustion engines. The returned exhaust gas is combined with fresh air, and both the exhaust gas and fresh air typically contain some varying amount of water vapor. Condensation may occur, for example, when the warmer exhaust gas is mixed with the cooler fresh air. Such condensation over time may lead to poor combustion stability and/or degradation of engine system components due to sulfur based acid formation that reacts with the component materials.
Turbocharged engines often utilize a charge air cooler (CAC) to cool compressed air from the turbocharger before such air enters the intake manifold. Condensation may also form in the CAC depending on an amount of cooling provided by the CAC and an amount of humidity and/or water vapor in the intake air stream. Turbocharged engines with an EGR system, may exhibit higher amounts of water vapor in the intake air due to presence of water vapor in the recirculated exhaust gas, which is mixed with the fresh air before entering the turbocharger. In such a scenario where the intake air entering the CAC includes EGR, the condensation may become acidic and may potentially corrode the CAC housing. The condensation may also accumulate in the CAC housing and may be drawn into the engine, which may also potentially lead to poor combustion stability.
Prior methods for controlling condensation do not accurately predict when condensation would form in connection with EGR, CAC cooling of compressed intake air, and cooling of EGR upstream of compressor. For example, prior attempts to address the above condensation formation include disabling or limiting EGR and/or providing a drain in the CAC to drain condensation accumulated therein. Thus, while such engine systems work for their intended purpose, there remains a need for improvement in the relevant art.